How much grease should a bearing have?

The initial grease fill is typically calculated as G = 0.005 × D × B grams, where D is the bearing OD in mm and B is the width in mm. For regreasing, use 50% of this amount. Actual fill percentage depends on speed — 30-50% of free space is common.

What happens if I over-grease a bearing?

Over-greasing causes excessive churning, increased temperature, higher power consumption, and can lead to seal failure and grease leakage. At high speeds, over-greasing is more harmful than under-greasing.

What fill percentage should I use?

For low speed (n×dm 300,000): 25-35%. Sealed bearings from the factory are typically 25-35% filled.

How do I determine the grease volume for relubrication?

For periodic relubrication, use approximately G_regrease = 0.005 × D × B × 0.5 grams. This delivers fresh grease to the contact areas without overfilling the bearing cavity.

Does bearing type affect grease quantity?

Yes. Ball bearings have more internal free space than roller bearings of the same size. The formula G = 0.005 × D × B is a good approximation for all types, but the fill percentage should be adjusted based on bearing type and speed.

Free Engineering Tool #051

Bearing Grease Quantity Calculator

Calculate the recommended grease fill amount for rolling bearings. Formula: G = 0.005 × D × B. Enter bearing OD and width.

G = 0.005 × D × BGramsFill % Guide

Results

Grease Quantity (100% fill)

—

Adjusted Quantity (selected fill %)

—

Regrease Amount (~50% of full)

—

Volume (approx.)

—

Grease Quantity Formula

D — bearing outside diameter (mm)
B — bearing width (mm)
G — grease quantity (grams)

Fill Percentage Guide

n × d_m	Speed Category	Recommended Fill
< 100,000	Low speed	50–80%
100,000 – 300,000	Medium speed	30–50%
300,000 – 500,000	High speed	25–35%
> 500,000	Very high speed	20–30%

Practical Example

Example — 6208 Deep Groove Ball Bearing

Given: D = 80 mm, B = 18 mm

G = 0.005 × 80 × 18 = 7.2 grams (100% fill)

At 40% fill: 7.2 × 0.40 = 2.9 grams

Regrease: 7.2 × 0.50 = 3.6 grams

⚠️ Note: Over-greasing is the #1 cause of grease-related bearing failures. When in doubt, use less grease and rely on proper relubrication intervals.

Bearing Grease Quantity Calculator | G = 0.005 × D × B | Free Online Tool

Published by admin on February 15, 2026 February 15, 2026

Results

Grease Quantity Formula

Fill Percentage Guide

Practical Example